Microprocessors generally include a variety of logic circuits fabricated on a single semiconductor integrated circuit (IC). These logic circuits typically include a processor core, memory, and other components. Today's high-end processors include multiple processor cores on the same IC. For instance, multi-core processors such as chip multi-processors (CMPs) feature a multi-core structure that implements multiple processor cores within an IC.
Increased silicon efficiencies are now providing new opportunities for adding additional functionality into the processor silicon. As an example, applications are taking advantage of increased multi-threading capabilities realized from an increased number of processing cores in the same processor. Performance of a multi-core processor may be optimized by mitigating system interconnect latency issues and ensuring that aggregated processor cores appear as one caching agent in order to avoid scalability issues and interconnect saturation. Systems that include caches each associated with multiple cores typically are structured as split caches in which each cache acts as an independent cache domain. This increases the total number of coherence misses, thus increasing the misses per instruction. Split-caches also lose capacity due to replication of shared code/data in all the independent caches.